St. Paul: Energy Park Dr. vapor intrusion site

In a mixed manufacturing/commercial/residential area on Energy Park Drive just east of Raymond Avenue in St. Paul, concerns have risen related to the presence of perchloroethylene (PCE, also called tetrachloroethylene) in the soil and groundwater. The MPCA is working with two industrial properties in the area on contamination related issues. One has operated as a chemical distribution facility since 1946. Historic PCE spills are sources of PCE in soil and groundwater on that property. Cleanup work to address this contamination is ongoing. Soil vapor testing done by a consulting company in 2013 and 2014 found PCE-contaminated vapors in the soil near the chemical facility.

The issue: Vapor intrusion

The groundwater contaminated with PCE could release PCE vapor that can rise through the soil and seep through basement and foundation cracks into homes and other buildings, where it could be inhaled by people. This is known as “vapor intrusion.” If vapor intrusion is occurring, it is likely that vapors are higher in basements than on upper floors.

The remedy for the situation is installing a vapor ventilation system, which operates like a radon mitigation system. If a building has a radon mitigation system that was installed by a certified contractor and is functioning properly, it is likely that the problem of PCE vapor in the building’s indoor air is being addressed.

Long-term exposure to low levels of contaminants in indoor air increases the risk that some people might experience health effects. However, the amount of PCE that may be entering homes at this site is expected to be small and not likely to result in health impacts. Although the risk is currently believed to be small, it is avoidable. MPCA wants to identify and take steps to reduce or eliminate vapor intrusion where possible.

Map: West Energy Park Drive site

The map below shows which buildings are in the mitigation area. Click image for larger view.